Bowling shoes and methods for making the same



July 20, 1965 J. E. WHITCAS 3,195,244

BOWLING SHOES AND METHODS FOR MAKING THE SAME Filed Feb 20, 1963 2Sheets-Sheet 1 mmmwwmm y 1965 J. E. wHrrcAs 3,195,244

BOWLING SHOES AND METHODS FOR MAKING THE SAME Filed 'Feb. 20, 1963 2Sheets-Sheet 2 D Locuhon 4 I Loca'non 2 For Large Shoe Location ALocation I Ball of Foot |4 6 30a 30b 30c United States Patent 3,15,244BGWLHNG HUE AND METHQDS F'QR MAKHNG THE SAME .loseph E. Whiteas, 416Yale Ave, Cherry Hill, NJ. Filed Feb. 20, 1963, Ser. No. 260,350 Claims.(Cl. 362.5)

The present application is a continuation-in-part of my applicationSerial No. 107,153, filed May 2, 1961, now abandoned.

This invention relates to the improvement of bowling shoes and has foran object the provision of a bowling shoe having a substantially uniformeffective coefiicient of friction which is lower than the coefficient offriction of the normal sole and is substantially unaffected by humidityconditions.

When bowling, the bowler is required to wear special shoes designed forbowling so as to keep the approaches of the bowling alleys clean.Ordinary street shoes are not permitted to be used for bowling as theywould scar the smooth surface of the approach to the alleys and wouldalso leave rubber marks from soles or heels on the alleys approaches. Itis customary to construct bowling shoes differently from street shoesand they should never be used for street wear. The bowling shoe that isused on the foot on which you slide when delivering the ball normally isprovided with a leather sole and a special white rubber heel. The shoefor the other foot has both a white rubber sole and heel to prevent thebowler from slipping or falling off balance during his delivery steps.The tip of the rubber sole is provided with a small piece of leather toprevent the rubber sole from dragging on the approach when the bowlertakes his steps for delivery.

In order to insure that a bowler will have a proper and comfortableslide during delivery, it is necessary that the bowling alley approachbe maintained in smooth condition and kept clean. Constant use of thealleys today, however, does not permit proper care and many times theapproaches are dirty and sticky. Various factors contribute to thesurface condition of alley approaches. For example, when an approach isnew, dirty, or the air is humid and the alley is sticky, or some rubberhas rubbed off a bowlers shoes, conventional bowling shoes will notglide over the surface of the approach with case. As a result, thebowlers Slide is shortened or he comes to a quick stop throwing him offbalance, thus interfering with his delivery of the ball and possiblycausing him to fall and injure himself. The fear of stopping quickly,while delivering a bowling ball, has been known adversely to affect manya bowlers game.

Manufacturers of bowling equipment and bowling alley proprietorsrecognize this problem and, in an effort to overcome the sticky surfaceconditions of the approaches, they supply a powder normally placed atone side on the starting end of the app-roach to the alley. Beforestarting the ball, a bowler tests the approach with his sliding shoe andif he finds that it is sticky, he puts his sliding shoe in the powderand then commences to bowl. While he is delivering the ball, the powderquickly comes off of his shoe and is spread over the approach to thealley. The powder will make his slide easy but for the next bowler thepowder may have made the alley too slippery thus throwing off thelatters delivery. Such use of powder can even make the. other shoe whichyou dont slide on slippery and this is undesirable. Additionally, it ispossible for the powder to set off. the foul line buzzer by getting intothe beam of the photoelectric eye. Accordingly, it will be seen that theuse of powder is not the best way for controlling the bowlers slide overthe surface of the approach to the alley.

In accordance with the present invention there is provided an improvedbowling shoe which insures a bowler a more uniform slide and eliminatesthe need for the use of powder. In accordance with bowling shoesconstructed according to the present invention, there are applied to thesole thereof predetermined areas of tluoro carbon material at spacedlocations, at least one of which during use of the bowling shoe, isbeneath the ball of the foot on the wear surface of the sole, suchfluorocarbon areas having a low coefiicient of friction and beingsubstantially non-absorbent. The fluorocarbon areas are separated 'byother areas of the sole which have a higher coefficient of friction toprovide a bowling shoe having a substantially uniform effectivecoefiicient of friction over the wear surface which is lower than thecoefficient of friction of the normal wear surface of the sole and issubstantially unaffected by humidity conditions. The fluorocarbon areasshould be substantially co-planar with the wear surface of the sole andmay comprise thin layers of fluorocarbon material adhesively applied tothe wear surface of the sole or they may comprise inserts disposed inrecesses in the sole and having exposed surfaces of fluorocarbonmaterial. In the preferred form of the invention the inserts have aresilient or cushioned backing.

For further objects and advantages of the invention, and for a moredetailed understanding thereof, reference is to be had to the followingdescription taken in conjunction with the accompanying drawings inwhich:

FIG. 1 is an elevational view partly in section of an improved bowlingshoe embodying the present invention;

FIG. 2 is a bottom view of the bowling shoe shown in FIG. 1;

FIGS. 35 are fractional sectional views of modifications of the soleconstruction of the bowling shoes shown in FIGS. 1 and 2;

FIG. 6 is a diagram of a shoe sole useful in explaining the positioningof the fluorocarbon areas;

FIGS 7-11 are sectional views of a preferred modification of the soleconstruction and method of making the cushioned inserts used therein.

Referring to FIG. 1, there is shown a bowling shoe 10 having aconventional soft leather upper 11 and a white rubber heel 12. The soleis of two-ply constructionineluding plys 13 and 14 and since this is theshoe on which the bowler slides during his delivery, the ply 14 whichcomprises the tread or wear surface of the sole is made of leather. Asmay be seen in FIGS. 1 and 2, the wear surface of the sole beneath theball and toe area of the foot is provided with a plurality of recessesin which are disposed predetermined areas of fluorocarbon material 16."Fluorocarbon material is particularly suited for this application as itis a soft but durable material, absorbs no moisture and has a very lowcoefficient of friction. Any .of the various types of fluorocarbon resinor equivalents may be utilized, such for example aspolytetrafiuoroethylene sold under the trade-mark Teflon orpolychl-orotrifluoroe-thylene sold under the trademark Kel-F.

As may be seen in FIG. 1, the fluorocarbon members 16 have a thicknesscorresponding at least to the depth of the recesses in the tread or sole14 and thus the exposed or wear surfaces of the fluorocarbon members 16are substantially coplanar with the wear surface of the sole 14. This isimportant in order that the bowler will not feel the members 16 throughthe sole of the shoe while he is sliding on the approach. Otherwise itmight interfere with his balance or delivery. The inner or upper surfaceof the fluorocarbon members 16 may be provided with a cementable surfaceso that the fluorocarbon members 16 may be adhesively secured within therecesses in the sole 14.

The areas of the fluorocarbon members 16 are predetermined and are sopositioned in the wear surface of the sole Is as to provide a bowlingshoe with a substantially has been found that such uniformity can beobtained by utilizing areas of fluorocarbon material having a diam-.eter of approximately one-half to three-quarters of an inch andpositioned at spaced locations on the wear surface of the sole beneaththe ball and toes of the foot as illustrated in FIG. 2. While slightlylarger areas of fluorocarbon material may be utilized depending upon thesize of the shoe, in general, the fluorocarbon areas should not exceedmore than about fifty percent of the wear surface of the sole l4, i.e.,not more than fifty percent of the surface of the sole that engages thealley approach during the slide. Fluorocarbon resin has a coeflicient offriction in the order of 0.04 whereas leather has a much highercoeihcient of friction, for example, in the order of 0.6

(Handbook of Chemistry and Physics, 41st edition, 1959- 1960). Thus itwill be seen that by applying the fluorocarbon material areas Ti to theleather sole of the bowling shoe, the overall coelncient of friction ofthe wear surface of the sole 114 will be substantially reduced.

As the fluorocarbon material does not absorb moisture, it is unaffectedby humidity conditions and greatly minimizes loss'of slide due to theslightest dampness of the shoe sole or a liquid spot or sticky substanceon'the sole. Heretofore with conventional bowling shoes, when approachesbecame sticky and it was diflicult to slide to a stop at the foul line,the usual practice was to reduce the bowlers normal speed. Suchcorrective measures are not necessary with bowling shoes constructed inaccordance with the present invention since the fluorocarbon materialareas in the sole are substantially non-absorbent and 7 provide thebowling shoe with a substantially uniform efiective coefficient offriction which is lowerthan the coeflicient of friction of the .normalleather sole and is substantially unaffected by humidity conditions.

In MG. 3, there is shown a modification of the inventionwhere thefluorocarbon members 13 have been provided with a flange 1.7 at the rearthereof which is larger in diameter than the diameter of the recess inthe sole 14. The flange 17 is made of metal and is provided with'tangs17a which are struck from the metal discs 17 and embedded into thefluorocarbon members 18. The flange portion of the member 17 projectsbeyond the circumfer ence of the fluorocarbon member 18 and is securedbetween the plies 13 and 14; or the sole. struction no adhesive isnecessary to hold the fluorocarbon members 13 within the recessesin thesole .14.

In FIG. 4, there is shown another modification of the invention wherethe fluorocarbon members 21 are provided with a screw member 19 which isadapted to be threaded into a nut member 28 which is secured in theinner ply 13 of the sole. An insole 22 covers the nut members 26. Thescrew member 19 has been illustrated as being provided with a headportion 19a which prefer ably is knurled and is secured to thefluorocarbon member 21 as by molding or by means of a press fit. Thefluorocarbon member 21 is provided with a pair of recesses 231a whichare adapted to be engaged by a spanner Wrench for screwing thefluorocarbon member 21 into the recesses in the sole 14. p

In FIG. 5, there is shown a further modification of the invention andone which is readily adapted for providing conventional bowling shoeswith the new improvement of the present invention. In FIG. 5 it will benoted that the fluorocarbon material areas have been illustrated onenlarged scale as thin tapematerial 24 the rear surface of which isprovided with a layer of pressure sensitive ad hesive 24a. The pressuresensitive adhesive'24a for ex ample may be of the type sold under thetrademark Permacel and it has the desirable characteristic that itadheres tightly to the sole yet it leaves no adhesive on the shoe solewhen the tape is removed. It is of course to be understood that othersuitable types of adhesive may With this 1 con be used, such for exampleas rubber cement, contact cement and epoxy resin. As mentioned above,the thickness of the fluorocarbon tape material 24 in FIG. 5 .must bemaintained thin in order that the wear surface thereof will besubstantially co-planar with the wear surface of the sole 14.. Thefluorocarbon material 24 must not be so thick that the bowler will feelthe members 24 through the bottom-of the sole nor should thefluorocarbon material 24 be so thick that the bowler will be slidingonly on the fluorocarbon material, and not on a composite surfaceincluding both fluorocarbon material and leather areas. If thefluorocarbon tape members 24. are too thick they may become dislodgedwhen the bowler steps up onto the edge of the approach. Satisfactoryresults have been obtained with fluorocarbon tape having a thickness offrom about 1364" to; .012". By using disc shaped fluorocarbon materialor other shaped areas having a rounded leading edge any tendency for thematerial to be removed during the slide on the approach is minimized.

As shown in FIG. 2 the preferred location for the fluorocarbon areas isa triangular arrangement with one of the areas being substantiallybeneath the ball of the foot. To aid in positioning the fluorocarbonareas either in insert form or in tape form an explanatory diagram isshown in FIG. 6. The principal location is at 1 being the area under theball of the foot. Location 2 is to the right f location 1 in astraightline, the distance being dependent upon the size of the shoe.The position of location 2 is determined from the position oflocation 1. It willbe noted in FIG. 6 that the center of location 1 is Xdistance from the left hand edge of the sole. The center of location 2is determined. by measuring in the same distance from the right handedge of the sole. This distance has been indicated in FIG. 6 asdimension A and thus it will be seen that X is equal to A. It will alsobe noted that the distance between the centers of locations 1 and 2 hasbeen indicated in FIG. 6 by dimension C.

way between the centers of locations 1 and 2 and perpendicular to lineC. The centerof'location 3 is positioned along this perpendicular lineat a distance D which is equal to distance C. These are the threeimportant locations for the fluorocarbon resin areas. If the shoe isunusually large in size orif a fourth location is desired then suchlocation 4 is on the same. perpendicular line just above the location 3.The foregoing dimensions have been given looking atthe sole of the slideshoe for a right hand bowler, which shoe would be his left shoe. For aleft handed bowler the slide shoe would be the right shoe and thedimensions would start from the right side to the left.

It has been found that in many instances small particles of metal are onthe bowling alley approach and area surrounding it. Most likely theseparticles arefrom the automatic pin setters and are carried to theapproach area by the returning bowling ball. Additionally, hardparticles of grit have always been carried to the alley from =resinsurface because these areas, being thin, flex with the sole and resistpenetration.

When'using thick inserts of fluorocarbon resin (in the orderof /s it hasbeen found that such inserts are harder than leather or thinfluorocarbon tape and thus did not flex as much. As a result thisthicker fluorocarbon resin material has a tendency to pickup particlesof grit and metal which have an adverse effect on the slide. However, ithas been found that if the fluorocarbon inserts are made frommaterial-produced under substantial pressure the increased densityapparently makes up for the lack of flexing and they do resist theembedding of particles and accumulation of dirt. On the other hand, freebaked fluorocarbon resin material which is not made under substantialpressure apparently is not as hard or as dense and particles of grit andmetal become embedded therein more easily. While material of this lattertype can be cleaned periodically to renew its surface it is preferablethat the high density fluorocarbon material or thin fluorocarbon tapematerial be utilized as it eliminates the need for periodic cleaning.

Referring to FIG. 7 there is illustrated a preferred embodiment of theinvention. In FIG. 7 the fluorocarbon resin areas are produced in thesole by inserts which additionally include the advantages of the thintape construction. As shown in FIG. 7 the insert comprises a cup-shapedmember 30 of fluorocarbon resin which is filled with a resilient orcushioning material 31. The cushioning material may comprise varioussuitable materials having cushioning characteristics. However, neoprenerubber of approximately 60 durometer has been found to be satisfactory.The rubber cushioning 31 has a thickness of about /s corresponding tothe thickness of the outer layer 14 of the leather sole.

To provide the recesses in the sole of the shoe to receive the inserts,the sole is first marked according to the diagram illustrated in FIG. 6.A circular cutter is used and the cutter is inserted in the bottom ofthe shoe sole until the first layer 14 of the leather sole has been cutthrough. The cushioned fluorocarbon resin inserts are produced in thefollowing manner. As previously mentioned, one of the common types offluorocarbon resin is polytetra- A cup 30 is formed by placing a pieceof tape 30 of this material over the female die 33 and beneath the malemember 34 as shown in FIG. 8. The tape material 39a is provided with anetched surface 30b on the upper side thereof, such etched surface beingproduced by known methods so as to render the surface suitable forreceiving cement or adhesive. The tape member 30a may be heated eitherbefore placing it in the position shown in FIG. 8 or by heating the dies33 and 34. The male member 34 is moved downwardly into the positionshown in FIG. 9 and pressure is applied forcing the tape 30a down intothe die 33 thereby forming a cup. The tape is removed from the die andimmersed in water or other suitable medium for cooling. The excess tapematerial is trimmed off leaving the polytetrafluoroethylene cup-shapedmember 30 with the etching on the inner surface 30b thereof as shown inFIG. 10. The heating and cooling steps produce a more satisfactorycup-shaped member and help the cup retain its shape. The heat employedduring the forming operation is not critical but should not be so highas to remove the etched surface 30b on the inside of the cup 30.

As shown in FIG. 10, the cup-shaped member 36 has been inserted in aretaining fixture 35 having a diameter and depth corresponding to theoutside dimensions of cupshaped member 30. The bottom of the recess infixture 35 is provided with a knockout hole 36, the purpose of whichwill be described hereinafter. With the cup-shaped resin member 36positioned in the fixture 34 as shown in FIG. 10 it is ready to receivethe flexible or resilient cushioning member 31. As mentioned above, thecushioning member 31 is preferably made from rubber which allows thecup-shaped member 30 to flex during use in the bottom of the sole. Therubber member 31 may be punched from /s" rubber sheet material or it maybe molded to predetermined size so as to fill the inside of cup member30. It is preferable that the rubber member 31 have a radius at itslower end to accommodate the radius on the inside of the bottom of thecup 30. By providing the rubber member 31 with such radius there isachieved a longer wear of the insert since a sharp corner would tend toweaken the insert at that point. 7

Contact cement is applied to the inside surfaces of the cup member 30and to the side and bottom of the rubber disc member 31. The contactcement may be of any of the suitable known types. Such cements dryquickly in about 15 to 20 minutes. The rubber disc 31 is then pressedinto the resin cup 30 as shown in FIG. ll. A knockout pin is theninserted into the hole 36 and the completed cup-shaped insert is removedfrom the fixture 35. The insert may be left in the fixture 35 until thecement is thoroughly set or a number of the inserts may be wrapped intoa stack in the same manner as the wrapping of a stack of coins and thusthe Wrapper will maintain pressure on the sides of the cup until thecement is thoroughly set.

When the insert has been completed it is ready to be installed in thesole of the shoe. As shown in FIG. 7, the sole 14- has been providedwith a recess of appropriate diameter which is slightly larger than thediameter of the cup-shaped insert 30. The recess is cut to the depth ofthe thickness of the sole layer 14 which is approximately A3 thick. Therubber cushion 31 is also A3" thick and thus the thickness of the resintape is left exposed from the sole 14 until pressure is applied bystanding on it. Cup-shaped inserts have been satisfactorily producedfrom polytetrafluoroethylene tape having a thickness from .015 to .020".Thus when the cup-shaped insert is inserted in the recess and cementedin place by contact cement located between the upper surface of therubber cushion 31 and the intermediate layer 13 of the sole thecup-shaped member 34 will protrude from the sole 14 a distancecorresponding to the thickness of the tape until pressure is applied bystanding on it. When the bowler puts his weight on the sole of the shoe,the side walls of the inserts will be compressed against the sides ofthe corresponding recesses and the bottom surfaces of the inserts willbe compressed into the recesses, leaving the bottoms of the cup-shapedmembers 30 extending out from the sole 14 by only a few thousandths ofan inch. The side compression along with the adhesive holds the insertsin place and since these inserts include a cushioning member 31 as Wellas being formed from flexible resin tape 39 they can conform with thesole of the shoe. By reason of this flexible construction the cushionedcup-shaped inserts of FIG. 7 cannot be felt under the bowlers foot. Thisis an advantage over the solid inserts shown in FIGS. 3 and 4 sinceconsiderable care must be exercised in installing solid inserts in orderto avoid their being felt through the bottom of the sole.

To cooperate. with the resilient cup-shaped inserts the inner solelining 22 and the intermediate sole layer 13 are provided with airrelief holes 37, PEG. 7. This relieves the pressure within the recessesin the sole 14 when the bowlers weight is applied to the inserts. Thecup-shaped inserts as shown in FIG. 7 have several advantages over thesolid inserts in FIGS. 1 to 4 and the tape insert in FIG. 5. Thecushioned cup-shaped inserts require less fluorocarbon resin materialthan the solid inserts and thus are less-expensive to manufacture.Additionally, they include a cushioning member which insures that theywill not feel harder to the bowlers foot than the remainder of the soleof the shoe. The cushion member 31 being of a material which is readilysecured in place by contact cement enables the cup-shaped inserts to beeasily installed and retained in the recesses in the sole 14. Thiseliminates the need for mechanical attaching means such as the plate 17in FIG. 3 and the screw and socket arrangement shown in FIG. 4.

The cup-shaped embodiment is preferable to the tape modification shownin FIG. 5 since the edges of the cup are not exposed but instead areformed upwardly so that they extend into the recesses within the sole.This avoids any possibility of the edge of the fluorocarbon resinmaterial from being pulled off during use and the weight of the bowlerinsures good adhesive contact between the cushion member 31 of theinsert and the sole.

While preferred embodiments of the invention have been described andillustrated, it is to be understood that 'modifications thereof may bemade'within the scope of the appended claims.

What is claimed is:

1. A bowling shoe having a leather sole the wear surface of which isprovided with a plurality of predetermined areas of fluorocarbonmaterial'at spaced locations at least one of which, during use of theshoe, is substantially beneath the ball of the foot and all of which aresubstantially co-planar with said wear surface of said sole, saidfluorocarbon areas having a low coefficient of friction and beingsubstantially non-absorbent, and said fluorocarbon areas being separatedby other areas of said wear surface of said sole having a highercoefflcient of friction whereby said bowling shoe has a substantiallyuniform effective coefficient of friction which is lower than thecoefficient of friction of the leather sole and substantially unaffectedby humidity conditions.

2. A bowling shoe according to claim 1 wherein said areas offluorocarbon material each comprise a layer of polytetrafluoroethylenesecured to the sole by adhesive.

3. A bowling shoe according toclaim 1 wherein said areas of fluorocarbonmaterial each comprise a thin layer of fluorocarbon tape secured to thewear surface of said sole and having a rounded leading edgeto preventremoval of said tape during a slide.

4. A bowling shoe according to claim 1 wherein said sole includesrecesses formed therein, said fluorocarbon areas being positioned insaid recesses in said leather'sole, and means is provided for retainingsaid fluorocarbon areas in said recesses so that the wear surface ofsaid fluorocarbon areas are substantially co-planar with said wearsurface of said sole.

5. A bowling shoe according to claim 4 wherein said fluorocarbon areascomprise fluorocarbon members having structural means for retaining themin said recesses in said leather sole.

6. A bowling shoe having a sole the wear surface of which ischaracterized by separate areas of leather and fluorocarbon material,said areas of fluorocarbon material having a rounded leading edge and alower coeflicient of friction than said leather areas, and saidfluorocarbon material areas being substantially non-absorbent so as toprovide a bowling shoe with a composite wear surface having asubstantially uniform effective coefficient of friction which is lowerthan the co-eflicient of the normal leather sole and is substantiallyunaffected by humidity conditions.

7. A bowling shoe having a rubber heel, and a sole having a compositewear surface consisting of exposed areas of leather and fluorocarbonresin, said composite wear surface of said bowling shoe having asubstantially uniform effective coefficient of friction which is lowerthan the coeflicient of friction of the leather and substantiallyunaffected by humidity conditions.

8. A bowling shoe having a high'friction heel, and a sole having acomposite Wear surface consisting of exposed areas of leather andfluorocarbon resin, said leather having a coefiicient .of friction lessthan that of said heel and said fluorocarbon resin being non-moistureabsorbent and having a coeflicient of friction substantially less thanthat of said leather, whereby said composite wear surface of saidbowling shoe has a substantially'uniform effective coefficient offriction which is lower than the coeflicient of friction of said leatherbut higher than said coefficient of friction of said fluorocarbon resinand substantially unaffected by humidity conditions;

9. A bowling shoe having a high friction heel and a sole having acomposite wear surface consisting of exposed areas of leather andpolytetrafluoroethylene, said leather having a coeflicient of frictionless than that of said heel and said polytetrafluoroethylene beingnon-moisture absorbent and having a coefficient of frictionsubstantially less than that of said leather, said sole includingrecesses formed therein said polytetrafluoroethylene areas beingpositioned in said recesses in said sole, said polyg.tetrafluoroethylene areas comprising cup-shaped members filled withcushioning material, and means for retaining saidpolytetrafluoroethylene cup-shaped members in said recesses so that saidcushioning material is disposed within said recesses and the bottomsurfaces of said polytetrafluoroethylene cup-shaped members aresubstantially co-planar with said Wear surface of said sole.

16. For use in the sole of a bowling shoe to produce a composite wearsurface comprising exposed areas of leather and polytetrafluoroethylene,the improvement of a resilient. insert comprising a cup-shaped member ofpolytetrafluoroethylene having a coefficient of friction substantiallyless than that of leather, a cushioning member filling said cup-shapedmember, and means for securing said cushioning member within saidcup-shaped member.

11. The method of making a resilient insert for a bowling shoe whereinthe insert has a low coeflicient of friction comprising the steps ofheating a thin sheet of fluorocarbon resin having the characteristics ofa low coefficient of friction and being substantially non-absorbent, andthereafter shaping it into a cup, filling the cup with resilientcushioning material, and adhesively securing the cushioning materialwithin the cup.

12. A method of making a bowling shoe having a composite wear surfacecomprising cutting a plurality of recesses in the leather sole of thebowling shoe at triangularly spaced locations at least one of which,during use of the shoe is substantially beneatht to ball of the foot,positioning an insert of fluorocarbon material having thecharacteristics of a low coe ficient of friction and being substantiallynon-absorbent, in each of said recesses, each insert comprising arelatively thin cup-shaped piece of fluorocarbon material, the interiorof the cup being filled with resilient material and bonded thereto toprovide cushioning, and adhesively securing the resilient material ofthe inserts in each of the. recesses so that the bottom of eachcup-shaped piece of fluorocarbon material of the inserts when positionedwithin the recesses is substantially co-planar with the wear surface ofsaid sole thereby providing a composite wear surface of exposed areas ofleather and fluorocarbon resin.

13. For use in the sole, ofya bowling shoe to produce a composite wearsurface comprising exposed areas of leather'and fluorocarbon'resin, theimprovement of a resilient insert comprising a layer of cushioningmaterial and a layer of fluorocarbon resin adhesively secured togetherso that said insert when-positioned in a recess in said bowling shoe hasthe outer surface of said fluorocarbon resin exposed to form a part ofsaidcomposite wear surface, said fluorocarbon resin being selected fromthe group consisting of polytetrafiuoroethylene andpolychlorotrifluoroethylene. p

14-. A bowling shoe having a high friction heel and a sole having acomposite wear surface consisting of exposed areas of leather andfluorocarbon resin, said leather having a coefflcient of frictionlessthan that of said heel and said fluorocarbon resin being non-moistureabsorbent and having a coeflicient of friction substantially less thanthat of said leather, said sole including recesses formed therein, saidfluorocarbon resin areas being positioned in said recesses in said sole,said fluorocarbon resin areas comprising cup-shaped members filled withcushioning material, and means for retaining said fluorocarbon resincup-shaped members in said recesses so that said cushioning material isdisposed within said recesses and the bottom surfaces of saidfluorocarbon resin cup-shaped members are substantiallyco-planarwithsaid wear surface of said sole.

15. For use in the sole of a bowling shoe to produce a composite wearsurface comprising exposed areas of leather and fluorocarbon resin, theimprovement of a resilient insert comprising a cup-shapedmember offluorocarbon resin being non-moisture absorbent and having a coefficientof friction substantially less than that of leather,

a cushioning member filling said cup-shaped member, and means forsecuring said cushioning member within said cup-shaped member.

References Cited by the Examiner UNITED STATES PATENTS Re. 14,119 4/16Berenstein 3659 1,350,839 8/20 Rendle 3659 2,640,283 6/53 McCord 362.5

1 0 2,732,065 1/56 Marchese 3659 X 2,744,340 5/56 Gerber. 3,011,27212/61 Goldenberg 362.5

OTHER REFERENCES Plastic Bulletin, volume 12, 1950, pages 183-186,inclusive.

JORDAN FRANKLIN, Primary Examiner.

1. A BOWLING SHOE HAVING A LEATHER SOLE THE WEAR SURFACE OF WHICH ISPROVIDED WITH A PLURALITY OF PREDETERMINED AREAS OF FLUOROCARBONMATERIAL AT SPACED LOCATIONS AT LEAST ONE OF WHICH, DURING USE OF THESHOE, IS SUBSTANTIALLY BENEATH THE BALL OF THE FOOT AND ALL OF WHICH ARESUBSTANTIALLY CO-PLANAR WITH SAID WEAR SURFACE OF SAID SOLE, SAIDFLUOROCARBON AREAS HAVING A LOW COEFFICIENT OF FRICTION AND BEINGSUBSTANTIALLY NON-ABSORBENT, AND SAID FLUOROCARBON AREAS BEING SEPARATEDBY OTHER AREAS OF SAID WEAR SURFACE OF SAID SOLE HAVING A HIGHERCOEFFICIENT OF FRICTION WHEREBY SAID BLOWING SHOE HAS A SUBSTANTIALLYUNIFORM EFFECTIVE COEFFICIENT OF FRICTION WHICH IS LOWER THAN THECOEFFICIENT OF FRICTION OF THE LEATHER SOLE AND SUBSTANTIALLY UNAFFECTEDBY HUMIDITY CONDITIONS.